MEDIA AND BIOCHEMICAL TESTS Flashcards
(54 cards)
How do you perform Indole test?
Inoculation of Tryptone broth with inoculating loop
Indole test is usually performed to differentiate species of _____.
Enterobacteriaceae
In indole test, bacteria species are examined if they have the ability to produce?
Indole
In indole test, bacteria use an enzyme _____ to break down the amino acid tryptophan.
tryptophanase
What are the reagents used in indole test?
- Tryptone broth
- Kovac’s reagent (HCl, dimethylaminobenzaldehyde)
How do you perform MRVP test?
- Inoculate 2 glucose broth with an inoculating loop.
- After 48 hrs incubation, add few drops of Methyl Red to one tube, and Voges Proskauer reagents to the other tube
In MRVP test, it is performed to differentiate species of ?
Enterobacteriaceae
In MRVP test, MR is for testing?
Acid end products from glucose fermentation
In VP test, VP is for testing?
Acetoin production from glucose fermentation
Describe the positive and negative results in Indole test.
Negative: 3 layers; orange, clear, thin brown layer
Positive: 3 layers; cloudy orange, “cloudish clear”, red top layer
What are the reagents used in MRVP test?
- Glucose broth
- Methyl red
- 5% alpha-naphtol
- Ethanol
- KOH
- Deionized water
Describe the positive and negative results for MRVP test.
MR: positive result in coloration of red indicates pH below 6; a negative results in coloration of yellow (no acid production)
VP: positive result becomes red after adding reagents indicating presence of acetoin; negative result has no changes in color
How do you perform Citrate test?
Inoculate slant with inoculating loop
Citrate test is performed to differentiate species of ?
Enterobacteriaceae
Citrate test is selective for bacteria that has the ability to consume citrate as its sole source of _____ and _____ as sole _____ source.
carbon; ammonium; nitrogen
What are the reagents used in Citrate test?
- Simmon’s Citrate Agar (Sodium Citrate)
- Ammonium ion (nitrogen source)
- Bromothymol blue (pH indicator
Describe the positive and negative results of Citrate test.
Positive result is blue w/c indicates that bacteria metabolize citrate and produce an acid end product. Negative result remains green
How do you perform SIM test?
Stab SIM media w/ inoculating needle.
SIM test is performed to differentiate species of ?
Enterobacteriaceae
SIM test is used to determine the ability of bacteria to reduce the _____ into _____.
sulfure; H2S
What are the reagents used in SIM test?
- Sulfur w/ amino acid
- Cysteine
- Sodium thiosulfate
- Peptonized iron or ferrous sulfate
Describe the positive and negative results for SIM test.
H2S will react w/ iron and produce a black precipitate. Positive result has a black precipitate. Negative has no black precipitate.
How do you perform Urea hydrolysis test?
Inoculate Urea broth with inoculating loop
Urea hydrolysis test is performed to determine a bacteria’s ability to hydrolyze _____ to make ______ using the enzyme _____.
urea; ammonia; Urease